Artist James Hart Dyke was given unprecedented access to Britain's Secret Intelligence Service, as MI6 celebrates its 100th anniversary. He spent a year shadowing spies and illustrating their activities. This week's episode of "The Revealer" takes us behind the pictures, and shows us how things are not always what they seem.

Hart Dyke's work looks pretty ordinary at first glance. If you walked in off the street, you might think his art portrayed everyday images. But this slideshow features some of the images he created during that time, along with the backstories on the illustrations.